by scalableUnicon on 1/27/20, 3:18 PM with 187 comments
by dang on 1/27/20, 6:03 PM
by drcode on 1/27/20, 4:16 PM
Lots of cyptocurrencies use the same mining algorithm, i.e. they require the same type of puzzle to be solved to make money creating blocks. In recent years, lots of online services have sprung up to offer cloud mining, which people usually use to mine blocks on the bigger cryptocurrencies, like Bitcoin Core or Bitcoin Cash.
However, since the smaller cryptocurrencies, like Bitcoin Gold, have less users/miners, they also require easier "puzzles" to be solved, which opens an opportunity for any random person to pay some $$$ to hire a bunch of these cloud servers for a limited time and point them at these easier puzzles, which can cause such a smaller blockchain to get confused about account balances. The attacker can then re-spend the same currency multiple times to make a profit.
AFAIK there aren't really any good solutions to prevent this problem- For complex game-theoretic reasons, simply changing the mining algorithm to something different doesn't really offer much protection. (Some folks believe if these smaller currencies were to move to "proof of stake" it could help solve this problem, but this is an extremely contentious topic.)
by tgsovlerkhgsel on 1/27/20, 5:19 PM
Bitcoin Gold is the least relevant of the forks (worth ~$12 per coin while the main chain BTC is worth ~8750 and the two major forks BCH/BSV are worth around 300, and only 7 of the 20 largest exchanges (by liquidity, according to coinmarketcap) list it - even though most of them list plenty of altcoins/shitcoins. For comparison, Bitcoin Cash is listed on all of them, Bitcoin SV on 14 of them. Additional stats here: https://news.ycombinator.com/item?id=22160458
by est31 on 1/27/20, 4:12 PM
The journalist has missed an important part of the github gist that their story bases on:
> Based on Nicehash market price data for Zhash we estimate the cost of generating each reorg at around 0.2 BTC (~$1,700) and the attacker would have recouped around the same value in block rewards. Therefore, it is possible that the attacks were profitable if the double-spends succeeded at defrauding the attacker's counterparty, or break-even if the double-spends were unsuccessful. This suggests that a confirmation requirement on the order of tens of blocks for BTG is still far too few to make the budget constraint to launch an attack significant.
by propter_hoc on 1/27/20, 4:12 PM
by piker on 1/27/20, 3:56 PM
by gruez on 1/27/20, 4:14 PM
by bdcravens on 1/27/20, 5:26 PM
by granaldo on 1/28/20, 1:05 AM
https://www.coingecko.com/en/coins/bitcoin-gold
The market may not even understand what 51% is about
by AdrianB1 on 1/27/20, 7:52 PM
by H8crilA on 1/27/20, 11:59 PM
by bobmaxup on 1/27/20, 5:13 PM
by TazeTSchnitzel on 1/27/20, 6:07 PM
Perhaps they should require some multiple of (amount of the transfer / cost of the hashpower needed to mine one block)?
by latchkey on 1/27/20, 8:20 PM
by milansuk on 1/27/20, 4:52 PM
This is also true for blockchain browsers(and their api), which apps use to confirm the transaction(most of users don't run full node). The only way how 51% attack can be successful in the long term is that honest nodes(and blockchain browsers api) are re-configure to ignore double-spent(at least for a particular time period).
by s_gourichon on 1/27/20, 6:19 PM
This might help general awareness that minor coins without a differentiating technology are simply highly vulnerable uninteresting clones, not worth any attention and thus, value. Perhaps some would just disappear, in a spiral of lower value, lower hash rate, more vulnerability, till all miners leave towards other, stronger coins?
This might sanitize the whole cryptocurrency domain a little.
Or not?
by rootsudo on 1/27/20, 9:18 PM
by m3kw9 on 1/27/20, 4:56 PM
by redis_mlc on 1/27/20, 7:59 PM
by dajohnson89 on 1/27/20, 4:05 PM
by pwinnski on 1/27/20, 3:51 PM
by maitredusoi on 1/27/20, 5:14 PM
by jb775 on 1/27/20, 10:14 PM
by knocte on 1/27/20, 4:18 PM